About 36.6 million people on average tuned in to watch the show on ABC in the US on Sunday night, down 16% from the 43.7 million people who watched the show last year, according to Nielsen figures reported by The Wall Street Journal's CMO Today.

Over on Twitter, the picture was even bleaker. Nielsen's Twitter TV ratings show that just 5.9 million tweets about the Oscars were sent this year, down 47% on the 11.2 million Oscars-related tweets in 2014.

Actor Eddie Redmayne after winning the Oscar for best actor.
REUTERS/Mike Blake
Why the shocking performance? There are a few theories out there: There wasn't an equivalent of a Samsung selfie (which sparked 3.3 million retweets); host Neil Patrick Harris didn't live up to Ellen DeGeneres' performance last year; and many of the nominees were not hits at the box office, unlike in 2014 when "Gravity" won seven Oscars and "12 Years a Slave" came away with best picture.

However, the show had one bright spot: Facebook. In a blog post, the social network said 86% more users posted, liked, commented, or shared Oscars-related content from the previous year. The number increased to 21 million from 11.3 million people in 2014.

In terms of posts, that number went up 129% to 58 million.

Facebook created this video to show how the conversation around the Oscars played out in real time on the social network during the ceremony.